Files
IfcOpenShell/src/ifcviewer/SidecarCache.h
T
Dion Moult 07a5c59359 GPU instancing: streamer, viewport, shaders rewritten
Commit A of the instancing migration (Phase 3a).  The streamer now runs
the iterator with use-world-coords=false and dedupes by the geometry's
representation id, emitting a MeshChunk once per unique geometry and an
InstanceChunk per placement.  The viewport keeps geometry in local
coordinates (28 B/vertex, down from 32) and applies the per-instance
transform in the vertex shader via an std430 SSBO indexed by
gl_InstanceID + a per-draw uniform offset.  After streaming finishes
finalizeModel() stable-sorts instances by mesh_id, assigns each mesh a
contiguous range, and uploads the SSBO; render then issues one
glDrawElementsInstancedBaseVertex per mesh.

BvhAccel is reshaped to operate on a generic BvhItem (world AABB +
model_id) so it can drive instance-level culling, but the path is not
wired in yet -- every instance is drawn every frame in this commit.
Progressive-during-streaming rendering is likewise disabled: a model
appears when its SSBO is uploaded, not incrementally.  Sidecar cache
is stubbed (reads miss, writes are no-ops); the v4 on-disk format with
MeshInfo + InstanceGpu sections lands in Commit B.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-04-23 21:32:24 +10:00

80 lines
3.4 KiB
C++

/********************************************************************************
* *
* This file is part of IfcOpenShell. *
* *
* IfcOpenShell is free software: you can redistribute it and/or modify *
* it under the terms of the Lesser GNU General Public License as published by *
* the Free Software Foundation, either version 3.0 of the License, or *
* (at your option) any later version. *
* *
* IfcOpenShell is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* Lesser GNU General Public License for more details. *
* *
* You should have received a copy of the Lesser GNU General Public License *
* along with this program. If not, see <http://www.gnu.org/licenses/>. *
* *
********************************************************************************/
// NOTE: Sidecar format v3 is being rewritten to v4 (instanced geometry layout).
// During the instancing rewrite (Commit A) the cache is a no-op: reads always
// miss and writes always succeed without producing a file. Commit B will
// re-introduce the on-disk format with MeshInfo + InstanceGpu sections.
#ifndef SIDECARCACHE_H
#define SIDECARCACHE_H
#include "InstancedGeometry.h"
#include <cstdint>
#include <optional>
#include <string>
#include <vector>
#include <memory>
static constexpr uint32_t SIDECAR_MAGIC = 0x49465657; // "IFVW"
static constexpr uint32_t SIDECAR_VERSION = 4;
static constexpr uint32_t SIDECAR_ENDIAN = 0x01020304;
// Fixed-size element record. Strings are stored as (offset, length) pairs
// into a separate string table.
struct PackedElementInfo {
uint32_t object_id;
uint32_t model_id;
int32_t ifc_id;
int32_t parent_id;
uint32_t guid_offset;
uint32_t guid_length;
uint32_t name_offset;
uint32_t name_length;
uint32_t type_offset;
uint32_t type_length;
};
// Everything needed to display an already-tessellated model without
// re-running the iterator. v4 schema: instanced geometry.
struct SidecarData {
// Per-model GPU geometry (local coords). 28 bytes/vertex.
std::vector<float> vertices;
std::vector<uint32_t> indices;
// Mesh dictionary and per-instance data.
std::vector<MeshInfo> meshes; // indexed by local_mesh_id
std::vector<InstanceCpu> instances; // sorted by mesh_id
// Element tree metadata.
std::vector<PackedElementInfo> elements;
std::string string_table;
};
// v4 writer/reader are stubbed for Commit A — no disk I/O happens.
bool writeSidecar(const std::string& ifc_path,
const SidecarData& data,
uint64_t ifc_file_size);
std::optional<SidecarData> readSidecar(const std::string& ifc_path,
uint64_t ifc_file_size);
#endif // SIDECARCACHE_H